The form of a proposition has meaning in the following way. Consider a symbol “xRy”. To symbols of this form correspond couples of things whose names are respectively “x” and “y”. The things x y stand to one another in all sorts of relations, amongst others some stand in the relation R, and some not; just as I single out a particular thing by a particular name I single out all behaviours of the points x and y with respect to the relation R. I say that if an x stands in the relation R to a y the sign “xRy” is to be called true to the fact and otherwise false. This is a definition of sense.